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matroskaenc: correct muxing of ASS packets 

- split packets to store one ASS event line per Matroska block
 - reformat ASS events to Matroska modified format
 - extract display duration for ASS events to store as Matroska block duration

Originally committed as revision 15561 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Aurelien Jacobs 2008-10-04 22:57:56 +00:00
parent 291902c274
commit b7f4e76d3d
1 changed files with 61 additions and 0 deletions
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61
libavformat/matroskaenc.c
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@ -721,6 +721,65 @@ static int mkv_blockgroup_size(int pkt_size)
return size;
}
static int ass_get_duration(const uint8_t *p)
{
int sh, sm, ss, sc, eh, em, es, ec;
uint64_t start, end;
if (sscanf(p, "%*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d",
&sh, &sm, &ss, &sc, &eh, &em, &es, &ec) != 8)
return 0;
start = 3600000*sh + 60000*sm + 1000*ss + 10*sc;
end = 3600000*eh + 60000*em + 1000*es + 10*ec;
return end - start;
}
static int mkv_write_ass_blocks(AVFormatContext *s, AVPacket *pkt)
{
MatroskaMuxContext *mkv = s->priv_data;
ByteIOContext *pb = s->pb;
int i, layer = 0, max_duration = 0, size, line_size, data_size = pkt->size;
uint8_t *start, *end, *data = pkt->data;
ebml_master blockgroup;
char buffer[2048];
while (data_size) {
int duration = ass_get_duration(data);
max_duration = FFMAX(duration, max_duration);
end = memchr(data, '\n', data_size);
size = line_size = end ? end-data+1 : data_size;
size -= end ? (end[-1]=='\r')+1 : 0;
start = data;
for (i=0; i<3; i++, start++)
if (!(start = memchr(start, ',', size-(start-data))))
return max_duration;
size -= start - data;
sscanf(data, "Dialogue: %d,", &layer);
i = snprintf(buffer, sizeof(buffer), "%"PRId64",%d,",
s->streams[pkt->stream_index]->nb_frames++, layer);
size = FFMIN(i+size, sizeof(buffer));
memcpy(buffer+i, start, size-i);
av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, "
"pts %" PRId64 ", duration %d\n",
url_ftell(pb), size, pkt->pts, duration);
blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(size));
put_ebml_id(pb, MATROSKA_ID_BLOCK);
put_ebml_num(pb, size+4, 0);
put_byte(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126
put_be16(pb, pkt->pts - mkv->cluster_pts);
put_byte(pb, 0);
put_buffer(pb, buffer, size);
put_ebml_uint(pb, MATROSKA_ID_BLOCKDURATION, duration);
end_ebml_master(pb, blockgroup);
data += line_size;
data_size -= line_size;
}
return max_duration;
}
static void mkv_write_block(AVFormatContext *s, unsigned int blockid, AVPacket *pkt, int flags)
{
MatroskaMuxContext *mkv = s->priv_data;
@ -774,6 +833,8 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
mkv_write_block(s, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe << 7);
} else if (codec->codec_id == CODEC_ID_SSA) {
duration = mkv_write_ass_blocks(s, pkt);
} else {
ebml_master blockgroup = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, mkv_blockgroup_size(pkt->size));
duration = pkt->convergence_duration;